Endoscopic submucosal dissection using a carbon dioxide laser with submucosally injected laser absorber solution (porcine model)

Use of current automatic smoke evacuation system in flexible gastrointestinal endoscopy: Its feasibility and potential usefulness

Objectives

Flexible endoscopy does not have a system that can automatically evacuate surgical smoke generated in the gastrointestinal lumen. We aimed to investigate the feasibility and potential usefulness of automatic smoke evacuation systems in flexible endoscopy.

Methods

[Bench] After surgical smoke generated in the stomach was evacuated by the evacuator, the degree of residual smoke and gastric luminal collapse were evaluated to optimize the evacuator settings. [Animal] Insufflation, suction, and total operation time to complete the protocol of 10 cauterizations of the gastric mucosa were measured in three groups: "manual suction only," "manual suction with automatic evacuation (50% force)," and "manual suction with automatic evacuation (70% force)." The stability of endoscopic visualization and operability was evaluated by 10 endoscopists blinded to those suction settings, and the number of manual suctions, insufflations, and total operation time were measured.

Results

[Bench] The degree of residual smoke and gastric luminal collapse were inversely correlated. [Animal] When the automatic evacuator was partially used, there was no difference in the insufflation time, but the suction time (vs 50%; p = 0.011, vs. 70%; p = 0.011) and total operation time (vs. 50%; p = 0.012, vs. 70%; p = 0.036) were significantly reduced compared to manual operation only. Furthermore, manual suction with automatic evacuation (50% force) significantly improved the stability of endoscopic visualization and operability compared to manual operation only (p = 0.041, p = 0.0085).

Conclusions

The automatic smoke evacuation in flexible gastrointestinal endoscopy was potentially feasible and useful by improving the device setting.

Recent advances in endoscopic management of gastric neoplasms

The development and clinical application of new diagnostic endoscopic technologies such as endoscopic ultrasonography with biopsy, magnification endoscopy, and narrow-band imaging, more recently supplemented by artificial intelligence, have enabled wider recognition and detection of various gastric neoplasms including early gastric cancer (EGC) and subepithelial tumors, such as gastrointestinal stromal tumors and neuroendocrine tumors. Over the last decade, the evolution of novel advanced therapeutic endoscopic techniques, such as endoscopic mucosal resection, endoscopic submucosal dissection, endoscopic full-thickness resection, and submucosal tunneling endoscopic resection, along with the advent of a broad array of endoscopic accessories, has provided a promising and yet less invasive strategy for treating gastric neoplasms with the advantage of a reduced need for gastric surgery. Thus, the management algorithms of various gastric tumors in a defined subset of the patient population at low risk of lymph node metastasis and amenable to endoscopic resection, may require revision considering upcoming data given the high success rate of en bloc resection by experienced endoscopists. Moreover, endoscopic surveillance protocols for precancerous gastric lesions will continue to be refined by systematic reviews and meta-analyses of further research. However, the lack of familiarity with subtle endoscopic changes associated with EGC, as well as longer procedural time, evolving resection techniques and tools, a steep learning curve of such high-risk procedures, and lack of coding are issues that do not appeal to many gastroenterologists in the field. This review summarizes recent advances in the endoscopic management of gastric neoplasms, with special emphasis on diagnostic and therapeutic methods and their future prospects.

Use of lasers in gastrointestinal endoscopy: a review of the literature

Lasers emit highly directional light with consistent wavelengths, and recent studies have demonstrated their successful applications in gastrointestinal endoscopic therapy. Although argon plasma coagulators (APC) became the preferred treatment option due to improved safety profile and lower costs, advancements in laser and optic fiber manufacturing have reignited interest in laser treatment. Different laser wavelengths have distinct features and applications based on their tissue absorption coefficient. Lasers with shorter wavelengths are effectively absorbed by hemoglobin, resulting in a good coagulation effect. Near-infrared lasers have ability to ablate solid tumors, while far-infrared lasers can make precise mucosal incisions without causing peripheral thermal damage. Lasers have proven to be highly applicable to endoscopy devices such as endoscopes, endoscopic ultrasound (EUS), double-balloon enteroscopes (DBE), and endoscopic retrograde cholangiopancreatography (ERCP), making them a potent tool to enhance the effectiveness of endoscopic treatments with minimal adverse events. This review aims to help readers understand the applications and effectiveness of lasers in gastrointestinal endoscopy, with the potential to promote the development and application of laser technology in the medical field.

Diode Laser-Can It Replace the Electrical Current Used in Endoscopic Submucosal Dissection?

Background/Aims

A new medical fiber-guided diode laser system (FDLS) is expected to offer high-precision cutting with simultaneous hemostasis. Thus, this study aimed to evaluate the feasibility of using the 1,940-nm FDLS to perform endoscopic submucosal dissection (ESD) in the gastrointestinal tract of an animal model.

Methods

In this prospective animal pilot study, gastric and colorectal ESD using the FDLS was performed in ex vivo and in vivo porcine models. The completeness of en bloc resection, the procedure time, intraprocedural bleeding, histological injuries to the muscularis propria (MP) layer, and perforation were assessed.

Results

The en bloc resection and perforation rates in the ex vivo study were 100% (10/10) and 10% (1/10), respectively; those in the in vivo study were 100% (4/4) and 0% for gastric ESD and 100% (4/4) and 25% (1/4) for rectal ESD, respectively. Deep MP layer injuries tended to occur more frequently in the rectal than in the gastric ESD cases, and no intraprocedural bleeding occurred in either group.

Conclusions

The 1,940-nm FDLS was capable of yielding high en bloc resection rates without intraprocedural bleeding during gastric and colorectal ESD in animal models.

Off-label use of 0.4 % sodium hyaluronate teardrops: a safe and effective solution for submucosal injection in gastric endoscopic submucosal dissection

Background and study aims  Submucosal (SM) injection is a critical step in endoscopic submucosal dissection (ESD). In Japan, use of viscous solutions such as sodium hyaluronate are recommended; the commercially product available is MucoUp (Seikagaku Co. and Boston Scientific Japan Co., Japan). Nevertheless, MucoUp is expensive and unavailable in many Western countries. For the past 8 years, we have been using low-cost sterile teardrops solution composed of 0.4 % sodium hyaluronate (Adaptis Fresh, Legrand Laboratory, Brazil). This solution is readily available in drugstores with a cost of approximately US$ 10.00 for each 10-cc bottle. The aim of this study was to present the clinical outcome with off-label sodium hyaluronate use for SM injection in gastric ESD. Patients and methods  A single-center retrospective study of collected data investigating consecutive patients that underwent gastric ESD between 2012 and 2019. ESD was performed using 0.4 % sodium hyaluronate teardrop for SM injection and Flush Knife BT 2.5 (Fujifilm Co., Japan). The following data were analyzed: clinical-pathological features, en-bloc, R0 and curative resection rate, procedure duration, adverse events, and clinical outcome. Results  ESD was performed with sodium hyaluronate for submucosal injection in 78 patients. The en-bloc resection rate and R0 resection rate were 96.1 % and 92.3 %, respectively. The curative resection rate for epithelial lesions was 83.8 %. Adverse events occurred in 5 cases (6.3 %): delayed bleeding (3.8 %, 3 cases) and perforation (2.5 %, 2 cases); all managed successfully by clipping and thermal coagulation. The mean volume of sodium hyaluronate solution used per patient was 10 cc (SD: ± 8 cc). During follow-up (mean: 17 months; SD: ± 14.5 months), two patients developed metachronous lesions (2.5 %). Conclusions  Off-label use of teardrops with 0.4 % sodium hyaluronate for submucosal injection was demonstrated to be safe and able to provide an effective submucosal cushion that facilitates SM dissection in gastric ESD procedures.

Evaluations on laser ablation of ex vivo porcine stomach tissue for development of Ho:YAG-assisted endoscopic submucosal dissection (ESD)

Endoscopic submucosal dissection (ESD) is clinically used to remove early gastric cancer in stomach. The aim of the current study is to examine a therapeutic capacity of pulsed Ho:YAG laser for the development of laser-assisted ESD under various surgical parameters. Ex vivo porcine stomach tissue was ablated with 1-J Ho:YAG pulses at 10 Hz at different number of treatments (NT = 1, 2, and 3) and treatment speeds (TS = 0.5, 1, and 2 mm/s) without and with saline injection. Regardless of saline injection, straight tissue ablation showed that ablation depth increased with increasing NT and decreasing TS. At NT = 3 and TS = 0.5 mm/s, no saline injection yielded the maximum ablation depth (3.4 ± 0.3 mm), partially removing muscularis propria. However, saline injection confined the tissue ablation within a submucosal layer (2.1 ± 0.3 mm). Thermal injury was found to be 0.7~1.1 mm in the adjacent tissue with superficial carbonization. Circular tissue ablation (2 cm in diameter) at NT = 3 and TS = 0.5 mm/s presented that no saline injection yielded a reduction in the lesion area, whereas saline injection maintained the ablated lesion area. Histological analysis revealed that unlike no saline injection, saline injection ablated the entire mucosal layer without perforation in the muscular propria. The pulsed Ho:YAG laser can be a potential surgical tool for clinical ESD to incise a target lesion without adverse perforation. Further investigations will validate the efficacy and safety of the Ho:YAG laser-assisted ESD in in vivo porcine stomach models for clinical translation.

Innovative therapeutic endoscopy in the upper gastrointestinal tract: Review of Japan Gastroenterological Endoscopic Society Core Sessions

Workshops on "Innovative Therapeutic Endoscopy" for upper gastrointestinal tract diseases were held four times as the Japan Gastroenterological Endoscopic Society (JGES) Core Sessions at the 93rd to 96th Biannual Meetings of the JGES. A total of 48 research presentations (including two invited lectures) were reported, and various discussions were held on these topics. When the research presentations were categorized according to the therapeutic procedure, endoscopic submucosal dissection (ESD) was the most frequent with 28 presentations (58.3%), followed by laparoscopy endoscopy cooperative surgery (LECS) with six presentations (12.5%). When the research presentations were classified by the target organ of the therapeutic procedures, the duodenum was the most frequent with 26 presentations (54.1%), followed by the stomach with 13 presentations (27.1%). The most important issue was the establishment of a safe and reliable endoscopic resection method for duodenal lesions. Issues related to gastric ESD were establishing an efficient traction method and a method to prevent post-ESD bleeding in high-risk patients. Other important issues were establishment of an efficient traction method and methods of preventing delayed bleeding in high-risk patients who undergo gastric ESD, expansion of indications for minimally invasive treatment using LECS for gastric cancer, the development of endoscopic full-thickness resection (EFTR) for gastric submucosal tumors (SMTs), and improvement of per-oral endoscopic myotomy (POEM) for esophageal achalasia and per-oral endoscopic tumor resection (POET) for esophageal SMTs. Through the JGES Core Sessions, it is expected that the minimally invasive treatments using endoscopes developed in Japan will be further advanced.

New Development for Safer Endoscopic Submucosal Dissection using the Carbon Dioxide (CO2) Laser (Secondary publication)

Endoscopic Submucosal Dissection (ESD) has been increasingly accepted as a minimally invasive treatment for the patients with early gastrointestinal cancers. However, reliable ESD technique demands high maneuverability, and the success of the operation is dependent on each operator's skill. We have developed a novel laser endoscopic system for ESD to overcome such technique-related difficulties. Compared to conventional ESD using electrosurgical knives, an ESD method using the CO₂ laser offers the advantages of less risk of perforation and the prevention of extensive thermal damage, because the CO₂ laser is strongly absorbed by water. Furthermore, due to the non-contact technique associated with the CO₂ laser and adequate visualization of the treatment area, the laser system may provide every endoscopist with more precise and safer treatment.

Comparison of synchronous dual wavelength diode laser versus conventional endo-knives for esophageal endoscopic submucosal dissection: an animal study

BACKGROUND

Endoscopic submucosal dissection (ESD) is widely used for en bloc resection in early gastrointestinal cancer. However, it is technically complex with long procedure time and high adverse event rates with using conventional knives. The aim of this animal study was to verify the feasibility of ESD using a novel 980/1470 nm dual diode laser (DDL-ESD) in comparison with conventional knives (C-ESD) in esophagus.

METHODS

This was an in vivo animal study using eight porcine models. Four were allocated in DDL-ESD group and four were in C-ESD group. Every model underwent two ESDs to remove half circumferential esophageal mucosa. Each model's esophagus was harvested during postmortem at 24 h after ESD. Each specimen underwent gross inspection and histopathological examination was carried out. Procedure time, completeness of en bloc resection, adverse events (bleeding and perforation) and histological injury to muscularis propria were assessed.

RESULTS

A total of 16 ESD procedures were performed with 100% en bloc resection rate. The procedure speed in DDL-ESD group was significantly faster as compared to C-ESD group (0.27 cm²/min vs. 0.21 cm²/min, p = 0.001). The number of intraoperative bleeding points and the use of haemostatic forceps were significantly lesser in DDL-ESD group (4 ± 2 vs. 8 ± 3, p = 0.016; 1 ± 1 vs. 3 ± 2, p = 0.029). Histological assessment showed that injury to muscularis propria in DDL-ESD was milder than C-ESD. There was no perforation observed in both groups.

CONCLUSIONS

DDL-ESD technique appears to be safer and faster than C-ESD with less bleeding and injury to deep tissues.